Submandibular gland botulinum neurotoxin A injection for predicting the outcome of submandibular duct relocation in drooling: a retrospective cohort study

AIM: This study evaluated whether the effect of submandibular gland botulinum neurotoxin A (BoNT-A) injection can predict the outcome of submandibular duct relocation with sublingual gland excision (SMDR) in children with drooling. Furthermore, we compared the effectiveness of both procedures. METHOD: A retrospective cohort study was performed in 42 children and adolescents (25 males, 17 females; mean [SD] age at BoNT-A injection 11y [4], range 4-20y; mean [SD] age at SMDR 15y [4], range 7-23y) with cerebral palsy or another non-progressive developmental disability who had undergone both BoNT-A injection and SMDR for drooling. Main outcomes were the drooling quotient and the visual analogue scale (VAS) on drooling severity at 8 weeks and 32 weeks follow-up. RESULTS: Failure or success of previous BoNT-A injections had no influence on success of consecutive SMDR. Relative change in main outcomes showed no significant relation between BoNT-A injection and SMDR for any follow-up measurement. After 8 weeks, SMDR was more successful than BoNT-A injection in diminishing VAS (VAS 80.0% vs 54.3%; drooling quotient 56.2% vs 51.0%). After 32 weeks, both drooling quotient (64.3% vs 29.5%) and VAS (75.7% vs 37.1%) showed significantly higher proportions of success for SMDR. INTERPRETATION: The effect of submandibular BoNT-A injection does not predict subsequent SMDR success in drooling. Furthermore, SMDR has a larger and longer-lasting positive effect on drooling than BoNT-A injections. WHAT THIS PAPER ADDS: Submandibular botulinum neurotoxin A (BoNT-A) injection effect does not predict submandibular duct relocation with sublingual gland excision outcome. Submandibular duct relocation is more effective and more permanent than BoNT-A injection.